The present invention relates generally to scanning a patient to obtain images of a selected part of a patient, and, more particularly, to a method and system for generating optimal images of a selected part of a patient.
In the medical field, scanning technologies such as ultrasound, x-ray and magnetic resonance imaging are used to obtain images of internal parts of a patient. These images are useful to physicians and other health professionals to assist them in assessing the patient""s condition and deciding on appropriate medical treatment. Such scanning technologies can be used, for example, to view a foetus, blood flow patterns in arteries, or to scan organs for irregularities such as cysts.
A human body is a dynamic system, in that parts of the human body change over time. In many cases these changes are cyclical. For example, in the case of a blood vessel the dimensions of the blood vessel will change markedly depending on the amount of blood that is flowing through the blood vessel at a particular time. The amount of blood that flows through a blood vessel at a particular time depends, in part, on when the particular time occurs relative to the heartbeat or cardiac cycle of the patient. Specifically, when the patient""s heart forces out blood, there is a surge of blood through the blood vessels and the blood vessels are dilated; however, when the heart is relaxing after each heartbeat, the amount of blood flowing through the blood vessels is substantially reduced, and the blood vessels are no longer as dilated. Organs, such as the heart itself, will also differ in appearance markedly depending on when they are viewed relative to the pumping action of the heart.
When tracking dynamic parts of a patient, it is easy to be deceived regarding the condition of these parts due to their dynamic character. Returning to the blood vessel example, when scanning a blood vessel it is easy to be deceived regarding the condition of the blood vessel by the fact that blood is pulsing through the blood vessel. Say, for example, that a blood vessel is being scanned for points of constriction where blood flow is blocked. As the flow of blood through a blood vessel fluctuates due to the pumping action of the heart, there will be periods when there is very little blood flowing through the blood vessel. As the blood vessel pulsates with the fluctuation of blood flowing therethrough, the dimensions of the blood vessel will also vary. If a cross-sectional frame of data is obtained by scanning a cross-section of a blood vessel when there is an ebb in the flow of blood through that point of the blood vessel, then the blood vessel will have a much smaller diameter then it would have had when the flow of blood through the blood vessel is at its maximum. To one viewing an image constructed from a cross-sectional frame of data thus obtained, it may appear that a blood vessel is constricted, when, in fact, the blood vessel is not constricted, but is merely being viewed at a time in the blood flow cycle when there is an ebb in blood flow. Alternatively, it may be difficult to determine if the blood vessel is truly constricted, as one examining an image constructed from a cross-sectional frame of data will be aware that what appears to be a constriction may, in actuality, be due to an ebb in the flow of blood through the blood vessel.
Accordingly, there is a need for a system and method of coordinating the scanning of a part of a patient with body cycles in order for a scan to be taken at an optimal time relative to those body cycles.
An object of an embodiment of the present invention is to provide a system for obtaining an optimally-timed image of a selected part of a patient.
According to an embodiment of the present invention there is provided a scanning system for obtaining an optimal image of a selected part of a patient, wherein the selected part varies cyclically over time. The scanning system comprises (1) scanning means for scanning a cross-section of a selected part of the patient to generate a time-wise series of images of the cross-section; (2) image processing means for analyzing the time-wise series of images to determine a state of the selected part as shown in each image in the time-wise series of images; (3) image selection means for selecting the optimal image from the time-wise series of images based on the state of the selected part in the optimal image; and, (4) memory for storing the optimal image.
An object of one aspect of the present invention is to provide a method of obtaining an optimal image of a selected part of a patient at an optimal time.
According to one aspect of the present invention there is provided a method of obtaining an optimal image of a selected part of a patient being scanned, wherein the selected part varies cyclically over time. The method comprises the steps of (1) scanning the selected part to obtain a time-wise series of images of the selected part; (2) analyzing each image in the time-wise series of images to determine a state of the selected part as shown in that image of the time-wise series of images; and, (3) selecting a selected image from the time-wise series of images based on the state of the selected part in the selected image.
According to another aspect of the present invention there is provided a method of obtaining a plurality of images of a selected part of a patient being scanned by scanning the patient at a plurality of cross-sections, wherein the selected part varies cyclically over time. The method comprises the steps of, at each cross-section in the plurality of cross-sections, (a) scanning the patient to obtain an associated time-wise series of images of the selected part, (b) for each image in the associated time-wise series of images, analyzing the image to identify an state of the selected part at the cross-section, and (c) selecting an associated selected image from the associated time-wise series of images based on the state of the selected part at the cross-section in the associated selected image.